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Background: We aim to assess if refractive error or age may influence the repeatability of measurements using a swept-source biometer., Methods: A total of 61 subjects were evaluated with IOLMaster 700 acquiring measurements of axial length (AL), central corneal thickness (CCT), white-to-white distance (WTW), anterior aqueous depth (AQD), lens thickness (LT), and keratometry (K) readings. Repeatability was evaluated classifying the sample according to the refractive state and age by the calculation of the within-subject standard deviation (S w ), coefficient of repeatability, and intraclass correlation coefficient., Results: Very similar S w was acquired among groups for AL, CCT, and WTW. Differences found for AQD, LT, keratometry and astigmatism among refractive and age groups were not clinically significant. Refractive groups obtained a S w for AQD between 0.016 and 0.026, while for LT was between 0.023 and 0.029 mm. Besides, S w showed values from 0.014 to 0.029 mm for keratometry. Age groups obtained a S w of 0.025 and 0.016 mm for AQD, and 0.029 and 0.018 mm for LT, respectively. S w was 0.019 vs 0.018 mm for K1, 0.014 vs 0.031 mm for K2., Conclusions: IOLMaster 700 showed good repeatability for biometric and keratometric parameters in eyes classified according to their refractive error or age.

Background: Current advances in ocular surgery require the evaluation of differences in automated white-to-white (WTW) measurements between systems. We aim to analyze three different commonly used devices in clinical practice: the IOLMaster 700, the Atlas 9000, and the Sirius., Methods: Ninety right eyes of ninety healthy subjects were included. Measurements of WTW distances were taken with each device for all subjects in the same session and by the same observer. Statistical comparison was carried out by means of the rANOVA procedure and the Bonferroni post-hoc test. In addition, the Bland-Altman analysis was applied in order to perform pairwise comparisons., Results: Average WTW values obtained by the IOLMaster 700, the Atlas 9000, and the Sirius devices were 12.18 ± 0.40-mm, 12.32 ± 0.37-mm and 11.90 ± 0.37-mm, respectively. There were statistically significant differences in all pairwise comparisons. Mean differences revealed that the Atlas 9000 provided the highest WTW values, followed by the IOLMaster 700 values and finally by the Sirius results, which had the lowest values. The limits of agreement obtained in all pairwise comparisons were wide, with a range between 0.64 and 0.75 mm., Conclusions: According to our results, these three devices should not be used interchangeably for WTW diameter measurements during the clinical practice.

Background: The aim was to assess the optical quality of four Boston contact lens materials with an optical device based on Schlieren interferometry., Methods: The NIMO TR1504 (Lambda-X, Nivelles, Belgium) was used to measure higher-order aberrations and their corresponding root mean square values of four different rigid gas permeable contact lenses made from four different Boston materials: EO, ES, XO and XO2 . For each lens, 30 measurements were performed with two optical apertures: 3.0 mm and 6.0 mm. The modulation transfer function, point spread function, Strehl ratio and a simulation of the image provided by the lens were computed from the Zernike coefficients measured up to the fourth order., Results: The root mean square error of higher-order aberrations varied significantly with material type for both optical apertures (p < 0.01). The largest difference was obtained between the Boston EO and the Boston ES materials (for a 6.0 mm aperture), the mean difference being (8.3 ± 0.2) × 10(-2) µm. The modulation transfer functions, point spread functions and Strehl ratio values were similar among all Boston materials at the smaller optical aperture; however, differences between each material were more apparent for the 6.0 mm aperture, with the Boston ES material exhibiting the best optical quality., Conclusions: In terms of all metrics analysed, all Boston materials examined showed comparable optical quality for a 3.0 mm aperture but the Boston ES material displayed the best optical quality for a 6.0 mm optical aperture., (© 2016 Optometry Australia.)

Purpose: The aim was to study the interchangeability of various devices that measure anterior chamber depth (ACD) and white-to-white (WTW) distance., Methods: Eighty right eyes of eighty patients aged 20 to 40 years were included. Their spherical equivalent ranged from -4.25 to +1.00 dioptres. Each eye's ACD and the WTW distance were measured using the following devices: a Castroviejo surgical calliper, CA-200F Corneal Analyser, Orbscan II, Pentacam HR and IOLMaster 500., Results: The Pentacam HR measured significantly greater ACD (p < 0.01) than the other two devices, whereas IOLMaster 500 and Orbscan II yielded comparable (p > 0.01) distances. Nonetheless, in every device comparison, the mean difference was within clinically acceptable limits. The device comparison showed that for WTW distance measurements IOLMaster 500 yields the greatest value (p < 0.01), whereas CA-200F Corneal Analyser yields the smallest one (p < 0.01)., Conclusion: Pentacam HR, Orbscan II and IOLMaster 500 can be used interchangeably to measure ACD, whereas Orbscan II, IOLMaster 500, Castroviejo surgical calliper and CA-200F Corneal Analyser cannot be considered interchangeable, when it comes to measuring WTW distance., (© 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.)

Background: The aim of this study was to analyse the visual quality of the AcrySof IQ SN60WF(®) intraocular lens (IOL) when combined with different corneal profiles., Methods: Ten eyes of 10 participants with no prior history of refractive or cataract surgery were evaluated. An adaptive optics visual simulator was used to simulate the wavefront aberration pattern of an aspheric aberration-correcting IOL (AcrySof IQ SN60WF(®)). Normal corneas (group A), low and high myopic corneal ablations (groups B and C, respectively) and low and high hyperopic corneal ablations (groups D and E, respectively) were also simulated. Monocular distance visual acuities at 100, 50 and 10 per cent of contrast were measured., Results: At 100, 50 and 10 per cent contrast, no differences were found between groups A and B (p > 0.06 for all contrasts). Group A obtained better values than groups C, D and E for all contrasts (p = 0.031, p = 0.038, p = 0.032 at 100, 50 and 10 per cent of contrast, respectively). At the same time, group B obtained better values than groups C, D and E (p = 0.041, p = 0.042, p = 0.036 at 100, 50 and 10 per cent of contrast, respectively). Within the five groups, the worst results were always obtained for group E (p = 0.017, p = 0.021 and p = 0.025 at 100, 50 and 10 per cent of contrast, respectively)., Conclusions: The results suggest that the aspheric aberration-correcting IOL studied provides comparable results, when it is combined with normal corneas and with corneas with simulated low myopic ablations. When negative amounts of residual spherical aberration after cataract surgery are expected to be achieved, IOLs with more positive spherical aberration should be considered., (© 2013 The Authors. Clinical and Experimental Optometry © 2013 Optometrists Association Australia.)

Background: The aim was to evaluate the visual performance provided with a contact lens-based pinhole design against a simultaneous vision multifocal contact lens., Methods: In a cross-over study at the University of Valencia, 22 presbyopic patients were evaluated using an artificial pupil fitted on the non-dominant eye and the simultaneous vision PureVision Multifocal contact lenses. After one month of contact lens wear, binocular distance visual acuity (BDVA), binocular near visual acuity (BNVA), defocus curve, binocular distance contrast sensitivity, binocular near contrast sensitivity, and stereoacuity were measured, under photopic conditions (85 cd/m(2)). In addition, binocular distance visual acuity and binocular distance contrast sensitivity were examined under mesopic conditions (5 cd/m(2))., Results: Mean binocular distance visual acuity for pinhole and PureVision Multifocal were 0.02 ± 0.04 and 0.01 ± 0.04 logMAR under photopic conditions and 0.16 ± 0.06 and 0.12 ± 0.04 logMAR for binocular near visual acuity under mesopic conditions, respectively. No statistically significant differences were found between both types of lenses at distance for both lighting levels and intermediate distances (p > 0.05). There was a significant difference at near vision under photopic conditions (p = 0.03). Binocular distance contrast sensitivity revealed statistically significant differences between the pinhole system and PureVision Multifocal for six and 12 cpd (cycles per degree) spatial frequencies at the two luminance levels, while for near vision, differences were also significant for 18 cpd. Stereoacuity was better with PureVision Multifocal (127 ± 49.3 seconds of arc) compared with the pinhole lens (220.2 ± 32.3 seconds of arc, p = 0.004)., Conclusion: Pinhole and PureVision Multifocal contact lenses provide good binocular vision for distance and functional intermediate vision. Although it was better with the PureVision Multifocal, near vision was not satisfactory for either of the two contact lens options., (© 2012 The Authors. Clinical and Experimental Optometry © 2012 Optometrists Association Australia.)

Purpose:   The aim was to assess visual performance after PureVision high addition multifocal contact lens (PM) fitting through contrast sensitivity measured under different illumination levels for both distance and near., Methods:   In a cross-over study, 20 presbyopic patients were randomly assigned to PM or spectacles. Near contrast sensitivity was measured with the Vistech VCTS 6500 system. Distance contrast sensitivity and distance visual acuity (VA) were measured with the Functional Vision Analyser under photopic (85 cd/m(2) ) and mesopic (3.0 cd/m(2) ) conditions, the latter also under two levels of induced glare: 1.0 lux and 28 lux. Near VA was measured by logMAR charts under approximately 80 cd/m(2) luminance settings., Results:   Average monocular spectacle corrected and PM VA were -0.02 ± 0.05 and 0.03 ± 0.05 logMAR for distance photopic, 0.16 ± 0.10 and 0.23 ± 0.07 logMAR for distance mesopic and -0.03 ± 0.05 and 0.05 ± 0.06 logMAR for near photopic, respectively. Average binocular spectacle corrected and PM VA were -0.05 ± 0.07 and -0.01 ± 0.03 logMAR for distance photopic, 0.10 ± 0.06 and 0.18 ± 0.05 logMAR for distance mesopic and -0.08 ± 0.06 and 0.02 ± 0.05 logMAR for near photopic, respectively. Statistically significant differences were found between the contrast sensitivity with the two types of correction for both distance and near, with spectacle correction being better in all cases., Conclusion:   PureVision multifocal contact lenses preserve good VA and good visual performance under real-life conditions., (© 2011 The Authors. Clinical and Experimental Optometry © 2011 Optometrists Association Australia.)

Purpose: The aim was to determine the efficacy of two artificial eye-drop formulations by analysing the lower tear film meniscus volume through a commercial high-resolution spectral-domain optical coherence tomographer., Methods: Twenty dry eye patients (12 men, eight women, aged 57.5 ± 8.4 years) with refractive errors from -2.50 to +0.75 D (mean -1.34 ± 1.02 D) and cylinders lower than 1.00 D were examined. Tear meniscus volume was measured before, immediately after and 10, 30 and 60 minutes after instillation using the Copernicus high-resolution spectral-domain optical coherence tomographer (Optopol Tech SA, Zawiercie, Poland). Volume was calculated from the local area obtained from tomograms considering a regular distribution of the tear meniscus across the eyelid. Ten subjects were randomly assigned to first receive either polyethylene glycol (Blink Intensive, Abbot Medical Optics Inc, CA, USA) or hypromellose (Artific, Farma-Lepori SA, Barcelona, Spain) three times daily in both eyes for one month. Measures were then repeated and after a one-week wash-out period they were switched to the other eye-drop for another month., Results: Mean baseline volume was 0.38 ± 0.10 µL, while mean baseline volume after the wash-out period was slightly higher, 0.39 ± 0.10 µL (p = 0.638). Analysis of variance showed significant differences in meniscus volume with time after instillation with both formulations (p < 0.001), mean volume decreasing with time. At 30 and 60 minutes following instillation, values decreased to almost baseline (average difference 0.02 ± 0.03 µL at t(30), p = 0.016 and 0.01 ± 0.01 µL at t(60), p = 0.098)., Conclusion:   An increase in tear film meniscus volume in dry eyes from the use of eye-drops has been shown. High resolution imaging of lower tear film meniscus with clinical optical coherence tomography systems provides useful measures of tear volume. Both formulations assessed in the present study are efficient in increasing tear meniscus volume and reducing dry eye signs and symptoms, although results in terms of increase in meniscus volume were higher with the polyethylene glycol formulation., (© 2011 The Authors. Clinical and Experimental Optometry © 2011 Optometrists Association Australia.)

Background:   To evaluate near stereoacuity with the balanced Proclear Multifocal simultaneous vision contact lens., Methods:   Twenty-five presbyopic subjects were fitted binocularly with the Proclear Multifocal contact lens and with distance contact lenses combined with reading spectacles, which served as controls. After one month, stereoacuity was measured using the vectographic Titmus and Random dot stereotests and the Howard-Dolman (HD) apparatus under photopic conditions (85 cd/m(2) ) at 40 cm. Binocular high-contrast visual acuities (BHCVA) at distance and near were examined., Results:   For the multifocal group, mean stereoacuity with the Howard-Dolman method was 22.40 ± 8.23 seconds of arc. Using the Titmus and the Random dot sterereotests, the values were 56.40 ± 18.00 and 54.80 ± 20.23 seconds of arc, respectively. For the SCL group, mean stereoacuities were 19.9 ± 4.6, 51.2 ± 16.4 and 51.2 ± 20.88 seconds of arc, with the Howard-Dolman, Titmus and the Random dot, respectively. There were no statistically significant differences among groups for Howard-Dolman (p = 0.07), Titmus (p = 0.10) and Random dot (p = 0.17) stereotests. No statistically significant differences were found between the Titmus and the Random dot stereotest values (multifocal group: p = 0.30 and SCL group: p = 0.50), however, these values differ significantly from those found using the Howard-Dolman method for both groups (p < 0.001). For the multifocal group, BHCVA was -0.007 ± 0.060 and 0.012 ± 0.063 logMAR for distance and near vision, respectively. For the SCL group, these values were -0.02 ± 0.05 and -0.01 ± 0.06 logMAR, for distance and near vision, respectively. Comparing both groups there were no statistically significant differences between groups for either distance (p = 0.08) or near (p = 0.09)., Conclusions:   The Proclear Multifocal contact lens provided good distance and near visual acuity preserving stereopsis. Multifocal optics with one lens biased to distance viewing and the other lens biased toward near viewing minimally affects stereoacuity., (© 2010 The Authors. Clinical and Experimental Optometry © 2010 Optometrists Association Australia.)

During the past years, the wish to become independent of spectacles has been growing among cataract and presbyopic patients due to many factors, such as the increase in near visual demands, the aesthetic need for a spectacle-free image and ageing of refractive surgery patients, among others. This review assesses recently published studies that analyse visual and optical performance through different metrics of eyes implanted with multifocal intraocular lenses (IOLs), particularly hybrid IOL designs. The published evidence suggests that hybrid multifocal IOLs provide very good outcomes in a number of visual and optical performance parameters. Patients implanted with this type of IOL obtain a satisfactory full range of visual functions, including patients of particular characteristics such as highly ametropic or post-LASIK.